In the past, methods of forming a circuit pattern by printing processes, such as screen printing, a dispenser method, ink jet printing, and electrophotographic printing, have been often used because the circuit pattern can be formed conveniently. In these methods of forming a circuit pattern, a conductive microparticle dispersion liquid made by dispersing conductive particles into a solvent, or a toner made by containing conductive material into a resin is used. Then, a target pattern is formed by coating or by electrostatic adsorption, and is heated and burned and thereafter the particles are fused to each other to be conductive, thereby forming wirings.
An example of forming a circuit pattern in a substrate surface is described in Patent Document 1. In the method of forming a wiring board described in this official gazette, in order to reduce disconnections of the conductor wirings formed from a conductive ink, or delamination from a substrate, a substrate containing a resin composition, which exhibits adhesive properties for the conductor wiring after undergoing a predetermined temperature history, is prepared, and a conductive ink is applied to the surface of this substrate. Then, the substrate and the conductive film pattern formed from the conductive ink are heated and cooled based on the predetermined temperature history, thereby providing adhesive properties to the substrate. Accordingly, the conductive film pattern is converted into the conductor wiring.
Another example of forming a circuit pattern in a substrate surface is described in Patent Document 2. In the method of forming a wiring pattern described in this official gazette, in order to prepare a wiring pattern in various substrate materials with high drawing accuracy, a release layer is formed in the transfer sheet surface of a highly heat resistant and flexible film. Then, in the surface of this release layer, a fine wiring pattern is drawn with a metal nano particle dispersion liquid by screen printing or ink jet printing. Then, the wiring pattern is heated and burned. On the other hand, an adhesive layer is applied onto the substrate to be transferred, and the transfer sheet is adhered thereon and is then compression-bonded to each other and heated, so that the wiring pattern is transferred to the substrate to be transferred.    Patent Document 1 JP-A-2005-347571    Patent Document 2 JP-A-2004-247572